1. Train Your Brain

• The default mode network of our brain, responsible for mind-wandering and creativity, needs to be turned down when we want to work for any length of time.  
• The brain's dorsal attention network - the part that helps us make decisions and focus on a task - ...

We've trained our brains to be unfocused. 

Practice concentration by turning off all distractions and committing your attention to a single task. Start small, maybe five minutes per day, and work up to larger chunks of time.

In order to improve your focus, you should actually try focusing on one task and one only. Therefore, make sure all possible distractions are being blocked, so you can devote yourself to only one task at a time. And, very important, make a habit out of it. Otherwise, it might not work in the long...